Toward Lower-Cost Catalysts for Fuel Cell Electrodes

3 October 2006

Scientists at Los Alamos National Laboratory have developed a new class of hydrogen fuel-cell catalysts that exhibit promising activity and stability. The catalysts are made of low-cost nonprecious metals entrapped in a heteroatomic-polymer structure, instead of platinum materials typically used in fuel cells. Replacing platinum with the non-precious metal composite could reduce the cost of hydrogen fuel cells.

In research published recently in Nature, Los Alamos scientists Rajesh Bashyam and Piotr Zelenay describe tests conducted on a cobalt-polypyrrole-carbon (Co-PPY-XC72) composite. The composite, consisting of cobalt, polymer and carbon, was developed in research aimed at developing low-cost non-platinum catalysts for the polymer electrolyte fuel-cell (PEFC) cathode (site of the oxygen reduction reaction).

While the electrical energy producing activity of the catalyst is lower than that of platinum-based catalysts used in polymer electrolyte fuel cells, the new material shows exceptional performance stability for more than one hundred hours of continuous testing, a result never before obtained with non-precious metal catalysts in PEFCs. The materials perform reproducibly and at higher voltages.

Besides being made of inexpensive and environmentally benign materials, the chief advantage of these composite catalysts for oxygen reduction is that they can operate in the acidic environment of the polymer electrolyte fuel cell.

—Piotr Zelenay

Bashyam and Zelenay are investigating the nature of catalysts in a variety of composites. They are also part of a larger Laboratory effort aimed at developing new catalyst and electrode structures that could increase the current output from fuel cells.

The two biggest obstacles in making a commercially viable fuel cell have traditionally been high cost and inadequate durability. Our focus at Los Alamos is to attack those obstacles as a system in which you simultaneously strive for lower costs and higher durability.

—Ken Stroh, program manager for the Los Alamos fuel-cell effort

The US Department of Energy’s Office of Hydrogen, Fuel Cells and Infrastructure Technologies funds much of the PEFC fuel cell research at Los Alamos.

Comments

At the least, this research will help kill/dampen demand for platinum, and other high priced precious/rare metals. The market for them as catalysts is rising, thanks in part to refining demand in the petroleum industry. Nickel, vanadium, and iron (steels) are starting to look as good, if not better than platinum, due to advances in nanotech particle catalysts. Granted, this field will likely push the performance, durability, and capability of platinum/paladium based material as well, but many of us will reap the benefits of cheaper products, derived from affordable catalytic materials.

As a component of a hydrogen FC this technology is still hostage to the merits of hydrogen, but I wonder if it isn't more broadly applicable to low-temperature fuel cells. According to what I've read, the losses in Zn-air FC's are largely due to irreversibilities at the cathode. If this material can operate in an alkaline environment and reduce those irreversibilities, Zn-air just got a whole lot better.

"While the electrical energy producing activity is lower than that of platinum catalyst..."

How about way way lower than Platinum catalyst. The line graphs are misleading in that they show the A/cm-2 at the same levels, and yet, the scale of the new catalyst is 1/12th lower than that of Platinum. While Platinum is shown at 1.2A/cm-2, the new catalyst is at only 0.1A/cm-2. I don't know whether this means anything or not...any fuel cell expert out there, please kindly lend us your 2 cents.

I'm just hoping that the specific current output is not the limiting factor in the power density of a fuel cell stack. Even if it is, a PHEV using a fuelcell stack a fraction of that of a normal FCV coupled with a larger battery pack would still make FCV a viable option. Solving the cost problem will open the door for FCV's to become the much sought-after transportation technology of the 21st century. Some data on the efficiency of the new electrode would also be nice.

At the low temperatures at which a PEFC operates, you anyhow need large areas for heat exchange. The bulkiest components of a complete PEFC system are the intake air pre-heater and the coolant radiator, not the stack. Cooling in particular presents a significant packaging challenge for mobile applications, given the cross-section of a traditional engine compartment.

In any case, unsolved problems related to the economically and ecologically viable production, distribution and on-board storage of hydrogen still loom at least as large as the cost of the fuel cell stack.

Eliminating the (prospective) need for platinum will, however, ease cost pressures on other applications. A PEFC based on platinum catalysts may require 10 times as much of this precious metal as the aftertreatment systems of one ICE at similar rated power.

Note that even with credits available for e.g. HEVs, California emissions regs mandate that at least 2% of all vehicles sold by a major carmaker have to be true zero (tailpipe) emissions vehicles as of MY 2005. Without this legal requirement, the automotive and energy industries could invest their engineering resources more heavily and productively in HEVs, PHEVs, BEVs, HCCI combustion, clean diesel and alternate fuels. Each of these would bring greater benefits sooner and at lower cost than fuel cells ever will.

Regarding viability of H2 as transportation fuel, the Honda FCX seems to have solved the packaging problem and the traditionally lack of range of FCV. At a moderate pressure of 330 bars, this futuristic car has a range of above 500kms, good acceleration, high top-end speed, and a very sexy appearance. It remains to be seen how durable Honda new fuel cell stack will last and how low can they price this vehicle.

As for H2 production, storage and transportation, the best way is to transport crude oil or natural gas to the gas station and reform and compress the H2 on site to sell to customers. Since Honda and GM will offer at home H2 production and compression hardware, this means that H2 production at a gas station will be no problem.

In the future, Zinc or boron or some other suitable metals such as magnesium alloy, in their metallic elements, can be oxidized to release H2 at the gas station, and then the resulting metallic oxide will be transported back and reheated using solar thermal energy to reclaim the metallic metals again, thereby solving the problem of transportation and storage of H2 as renewable energy carrier.

The infrastructure developed for H2 from fossil fuels today will remain in place when H2 production will be gradually switched to renewable energy without requiring again a complete change of infrastructure.

As the Honda FCX demonstrates, H2-FCV's can double or triple the energy efficiency of liquid hydrocarbon fuels, thereby stretching the limited renewable energy resources and will greatly hasten the complete transformation to a totally-renewable-energy transportation system.
For example, it is estimated that biowastes is enough to support 1/3 of transportation energy requirement. If all cars in the street are FCV's with 60% efficiency versus an average of 20% efficiency of a regular gasoline car, then we can depend completely on renewable biowastes.

One of the most perspective ways i've lately read is to produce h2 with boron onboard of vechicle. Reaction between water vapour and boron gives you h2 and boronoxide. boronoxide will be collected but the h2 goes to fuel cell to produce electricity and heat. so you carry onboard only boron and water. This means you to need that expensive and complicated storage system for h20 on board or in "gas station". and boron is less active with water than ex. natrium.

In "gas stations" you return boronoxide and get pure boron. Boronoxide will be sent for recyling. Boronoxide will be reacted with magnesium which gives pure boron and magnesium oxide. Magnesium goes to magnesium oxide chlorinator where oxygen will be excreted. After that magnesiumcloride will go throw magnesium cloride electrolyser to separate clorine and magnesium.

A study conducted concerning hydropower showed all emissions from the laying of the first brick to the complete decomissioning of the plant and the three choices of least emissions per MW-hr produced (NOx, SOx, and CO2) were hydro, wind, and nuclear. Solar was significantly higher than any of these three but significantly less than any other power generation source (except geothermal which was somewhere just under solar).

it is true that i am a hot momma and that you can not relate! but i need some information about the process of renewing the PEFC fuel cell... so if any of you peoples that are like really smart and know a lot about this stuff, can you please email me the information that you have...
thanks,
hot momma

Hi all, just to share on the DME developments in China:
Since DME has an advantage of decomposition at lower temperature than methane and LPG, R&D for hydrogen source for fuel cell has been carried out. DME has a potential of feedstock for chemicals. DME to olefins is under development in Japan.

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DME productivity can be much higher especially if
country energy policies makes an effort comparable to
that invested in increasing supply.
By:
National Development Reform Commission NDRC
Ministry of Energy for Mongolia

Production of DME/ Methanol through biomass
gasification could potentially be commercialized
By:
Shandong University completed Pilot plant in Jinan and
will be sharing their experience.

Advances in conversion technologies are readily
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chemical feedstock
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Available project finance supports the investments
that DME/ Methanol can play a large energy supply role
By: International Finance Corporation